What is causing these stripes and tears?

[Durley]

The calculation for optimum angle is:
Arctan (layer height / pixel width) 

 

Note this is the angle that produces the smoothest finish on an angled surface by minimising the step size in the print. It doesn’t address distortion, tearing or other issues, it is just about optimising print fidelity.

[drduncan]

@MikeTrice There is a small amount of up and down movement in the build plate when grasped. I’ll investigate anti backlash nuts and hue on earth to fit one to the photon mono.

D

[MikeTrice]

If you have not already done so it is worth joining a Facebook group catering for the Photon Mono.

[Durley]

@drduncan is the distortion you are experiencing on a wagon that includes the floor as an integral part of the print? If so I would suggest trying printing without the floor which may be part of the problem by generating an enclosed volume during the printing process.

I have a similar but not so extreme issue on my 3 plank wagon. The lower wagon is printed with the floor included and shows slight distortion to the headstock and in the line of the side planking. The upper print is the same except with the floor removed, it does not have any distortion evident.

In my case I decided I could live with the distortion which is not that noticeable to the naked eye.

[MikeTrice]

Attached is an early attempt at printing a V2 body. Note the deformation around the front of the smokebox.

 

The way the normal printing process works is a section of the model is exposed against the FEP and then gets pulled up ready for repositioning  for the next layer. The print is stuck to the FEP and peels away. This takes a certain amount of force and as the FEP is flexible it will effectively bow. The force and amount of bowing is dependent on the area of the current layer against the FEP.

 

If the print encounters a sudden change in cross section when printing the additional required force and bowing of the FEP can cause surface blemished to appear. In the case of the V2 the hollow smokebox suddenly encounters the additional area of the smokebox door and results in the distortion shown. To resolve I had to modify the model to radius the inside transition from smokebox to smokebox door effectively smoothing out the sudden change.

 

Changing the angle of the print might work, it all depends on what you are trying to print. As @Durley states distortion could occur when encountering a wagon floor and removing the floor might solve the issue: